I see from your post frequency that you're concerned, but there's no immediate need for worry.

Even if the conversion process doesn't work, it won't harm the existing phpBB2 database. It only tries to copy (convert) the data towards to the new phpBB 3.x install. If it fails, you can just try again.

Additionally, could you please keep in mind that we have a six hour bumping rule on this website. If you have any new information within that time frame, please edit your older post. We won't forget about you.

Thanks for the tips but I have managed to convert it to 3.0.14 and it is running fine, however I have several Spam attacks, apparently on the same forum topic that I have disabled my board.

I guess I have to convert to 3.2.x although if there is a solution for blocking spam on the current 3.0.14, I would try it until I decide to convert when I am less busy. The spammers become members (without any email notification) and post on the same topic. I had some 10/day so Its quite nuiassance

I lost the touch of ACP but I think I have to check from Forum permissions.
I have this screensnapshot setting for the Forum.

I am having lot of users becoming members. Now I changed the setting that admin has to confirm new user registration, and maybe I blocked the spammers for a while but they are still are bypassing the spam countermeasure (3D grafic) and become inactive users. (unless they are human agents!)

they are still are bypassing the spam countermeasure (3D grafic) and become inactive users. (unless they are human agents!)

The graphic captcha are not any good. You should be using a non-Googleable Q&A.
With Admin activation, those inactive spammers would not be able to post until they are activated, unless you are allowing Guests to post.